Astronaut Kelly twins part of ground-breaking NASA experiment

Scott and Mark Kelly: Three-year, in-depth study will look at effects of long stays in space on the human body.

Commander Scott Kelly will return to space next year for the longest single space adventure for any American astronaut. Kelly will circle the earth aboard the International Space Station for 12 months. When he returns, Kelly and his identical twin brother Mark, a retired astronaut, will participate in an in-depth study on the effects of long stays in space on astronauts.

The 10 three-year studies will look at everything from the effects of space on the digestive tract and the immune system to how genes react as a result of orbiting the Earth for a prolonged period. The project will cost $1.5 million, the Irish Independent reports.

Studies of twins aid scientists in understanding environmental influences. Mark, who will stay on the ground, will serve as the ultimate “control” subject for his orbiting brother.

“This is a unique opportunity. We can study two individuals who have the same genetics but are in different environments for one year,” said Craig Kundrot, deputy chief scientist of Nasa’s human research program.

The studies were first proposed by the Kellys, the only identical twins to have flown in space.

“They have a very long-term vision,” said Dr. Andrew Feinberg, a researcher at the Johns Hopkins University School of Medicine and one of the investigators in the project, told the New York Times. “It’s kind of amazing.”

Feinberg will perform a full genome analysis of both men to study any epigenetic effects — how the environment changes genes and their function.

The brothers, aged 50, are both retired United States Navy captains. Mark Kelly, who is six minutes older than his brother and is married to former Congressman Gabrielle Giffords, has been to space four times, as a shuttle pilot and commander. He ended his last mission in 2011.

Scott Kelly’s previous trip to the International Space Station began in 2010 and lasted six months. When he returns to earth after his upcoming mission, he will have spent 540 days in space. He said that an extended expedition aboard the space station is easier now than in the past with better access to email and telephone communications as well as entertainment programming, exercise equipment and good air quality, reports the New York Times.

The Irish American twins trace their Irish heritage through their father, Richard Kelly, a retired police captain. In a 2006 interview with IrishCentral’s sister publication, Irish America magazine, it was revealed that the brothers were determined to go into space at an early age.

Their father said that when the boys were eight they told their Irish grandmother in Orange, NJ that they would be going up in space someday.

Their mother said she was not surprised.

"I really do believe there is a genetic predisposition for certain things," she told the magazine.